The invention relates to a urine measuring device and in particular to a urine measuring device comprising a drip chamber with an antireflux valve.
Urine measuring devices serve for collection of the urine leaving the patient""s body through a catheter. Germs from the environment may enter the measuring container of the urine measuring device and grow there. Such germs may enter the patient""s body via the connecting tube leading to the patient""s body and cause infection of the urinary passages. To prevent such infections urine measuring devices are generally provided with a Pasteur chamber at the place where the connecting tube leads into the measuring container. Said chamber comprises a drip chamber with a dropper on the supply side and an antireflux valve on the discharge side. In the drip chamber the liquid column coming from the connecting tube is stopped. The urine drops from a dropper tip and falls freely through the air without wetting the walls of the drip chamber. The germs are not capable of moving along the dry walls towards the patient""s body.
During a collecting phase (normally one hour) the urine measuring device is suspended vertically on the patient""s bed. At the end of the collecting phase the quantity of urine is recorded and the measuring container is discharged into the urine bag. For this purpose the measuring container is tilted by more than 90xc2x0. It would be possible that the refluxing urine wets the dropper and the inner walls of the drip chamber so that the germ barrier would be overcome. To prevent this it is common practice to provide an antireflux valve on the bottom of the drip chamber.
An antireflux valve in conjunction with said drip chamber is described in U.S. Pat. No. 3,965,900. Said antiflux valve comprises a valve flap closing a lateral opening of the drip chamber with the valve flap being biased into the closing position by a holding element. The holding element and the valve flap form a check valve. Said check valve comprises at least two parts of which the holding element has a complex form. Therefore the manufacture involves relatively high costs and efforts.
An antireflux valve is described in U.S. Pat. No. 4,334,537. Said antireflux valve comprises a valve chamber with a valve seat against which a valve disk is drawn. The valve disk is formed integral with a holding rod provided with spring-type anchoring elements at its ends. The manufacture of such a complex valve body involves considerable costs and efforts.
Further, it must be taken into consideration that together with the urine solids (blood clot, gravel) may be transported which deposit in the valve and keep it open.
A urine measuring device in which a check valve is provided at the lower end of the measuring chamber is described in German Patent Publication 41 37 074 A1. The check valve comprises a valve plate which presses against a circumferential valve seat arranged on the bottom side of the valve opening. No information is furnished on the valve plate fastener and the valve plate operation.
The object of the invention is to provide a urine measuring device comprising a drip chamber and an antireflux valve, which precludes the danger of malfunction caused by solids and which can be manufactured and assembled is an easy and inexpensive way.
The invention is based on the idea that the valve must generally be open but on the other hand be closed tight in the closing position. Further, the valve should be amply dimensioned to prevent deposition of blood clots or gravel. According to the invention the urine measuring device is provided with a valve plate comprising a freely movable loose part. This means that the valve plate is not permanently fixed to any place or any other part but is rather a freely movable part. The valve plate is a flat plate which does not comprise any shoulders etc. projecting from the plate plane. The valve plate fits from below closely to a valve seat when an external force exerted by the reflux liquid acts upon it. In the unloaded condition the valve plate is located apart from the valve seat so that valve opening is open. This means that the dripping urine can pass by gravity through the valve opening. If the urine measuring device is tilted for the purpose of discharging the measuring chamber or for any other reason, the urine contained in the measuring container presses the valve plate against valve seat thus sealing the latter. This prevents refluxing urine from entering the drip chamber and wetting its walls. Since the walls of the drip chamber remain dry, they do not form any bridges which allow germs to travel towards the patient""s body.
An essential advantage of the invention is that the valve is integrated in the measuring device housing and requires the valve plate as the only specific additional part. The parts of the valve housing may be integrated in the measuring device housing as a single unit so that separate manufacture or assembly is not necessary. The valve plate is a flat plate which requires no particular three-dimensional forming. It can rather be punched out of a suitable flat sheet material, preferably polyester sheet. The valve plate is relatively stiff and dimensionally stable and is preferably made of semirigid plastic material.
The valve plate is loosely supported between lateral guide elements. This means that the valve plate is at no place permanently fixed to the valve housing. The guide elements form a kind of cage in which the valve plate is movable. They are arranged in such a way that in each possible position the projection of the valve plate completely covers the valve opening.
The lateral guide elements are preferably made of ribs which extend inwardly from the valve housing wall with the valve housing having a larger cross-section than the valve opening.
Thus a large passage cross-section is available. Due to the absence of elastic tensioning means and due to a large free passage cross-section there is no danger that solid matter contained in the urine affect the functioning of the valve.
According to a further aspect of the invention the valve, except for the valve plate, forms an integral part of a measuring device housing containing the drip chamber. Here, no additional components need be incorporated in the housing during assembly. The valve plate is merely inserted into the cavity provided for this purpose without any fixing being required.
According to a preferred embodiment of the invention the measuring device housing comprises two housing parts which are attached to each other. The valve opening and the guide elements are components of the one housing part and a bracket supporting the valve plate is a components of the other housing part. For assembly purposes merely the two housing parts are attached to each other with the valve plate being interposed.
The cross-sectional area of the valve opening is preferably at least 70% larger than the internal cross-section of the dropper. This ensures an adequate dimension of the valve opening so as to prevent clogging.